With increasing emphasis being placed upon operational efficiency of motor vehicles and the desire of vehicle operators to prolong tire life, it has been increasingly recognized that users of motor vehicles should regularly monitor tire pressure. Frequent monitoring of tire pressure and maintanence of optimum pressure within each tire of a motor vehicle significantly improves vehicle fuel efficiency, increases operational vehicle safety, and prolongs tire life.
In most instances, tire pressure has been measured by application of an exterior gauge or other device to the conventional valve stem through which air is supplied to the tire interior. Mechanical gauges for this purpose are produced with substantial variations in quality, and are subject to mechanical deterioration and damage during their normal life. Hand held gauges are typically of a relatively small size, and are easily lost or misplaced, making them often unavailable when required by the user.
Wheel attachments for sensing tire pressure have been proposed in the past, but have been technically difficult to implement because of the rotational nature of the wheel on which the tire is mounted. Such monitors are typically restricted to usage as limit sensors and indicators which relay signals to the vehicle user indicating whether tire pressure is above or below a preset value.
The present invention arose from a desire to provide accurate visual monitoring of tire pressure without use of any external device apart from the wheel itself. The wheel includes an integral pressure sensor and associated electronic circuitry capable of displaying visual tire pressure information at an exterior wheel surface. In a preferred embodiment, this information is presented in the form of a numerical readout respresenting instantaneous tire pressure.